<!doctype html>
<html>
<head>
<meta charset="utf-8">
    <meta name=viewport content="width=device-width,initial-scale=1">
<title>HTML5 Canvas爱心表白动画特效DEMO演示</title>
    <script src=https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js></script>
<style>
html, body {
  height: 100%;
  padding: 0;
  margin: 0;
}
    .hidden{
        transform: scale(0);
        transition: s;
    }
    .show_like{
        /*transform: scale(0.5);*/
        transition: 1s;
        animation: show 1s ease-in-out;
    }
    @keyframes show {
        0% {transform: scale(0.5);}
        40% {transform: scale(1.3);}
        60%{transform: scale(1.1);}
        70%{transform: scale(1.3);}
        100% {transform: scale(1.0);}
    }
</style>

</head>
<body>


<script>
    likes();
    function likes() {
        /*
 * Settings
 */
        var settings = {
            particles: {
                length: 500, // maximum amount of particles
                duration: 2, // particle duration in sec
                velocity: 100, // particle velocity in pixels/sec
                effect: -0.75, // play with this for a nice effect
                size: 30, // particle size in pixels
            },
        };

        /*
 * RequestAnimationFrame polyfill by Erik M?ller
 */
        (function () {
            var b = 0;
            var c = ["ms", "moz", "webkit", "o"];
            for (var a = 0; a < c.length && !window.requestAnimationFrame; ++a) {
                window.requestAnimationFrame = window[c[a] + "RequestAnimationFrame"];
                window.cancelAnimationFrame = window[c[a] + "CancelAnimationFrame"] || window[c[a] + "CancelRequestAnimationFrame"]
            }
            if (!window.requestAnimationFrame) {
                window.requestAnimationFrame = function (h, e) {
                    var d = new Date().getTime();
                    var f = Math.max(0, 16 - (d - b));
                    var g = window.setTimeout(function () {
                        h(d + f)
                    }, f);
                    b = d + f;
                    return g
                }
            }
            if (!window.cancelAnimationFrame) {
                window.cancelAnimationFrame = function (d) {
                    clearTimeout(d)
                }
            }
        }());

        /*
 * Point class
 */
        var Point = (function () {
            function Point(x, y) {
                this.x = (typeof x !== 'undefined') ? x : 0;
                this.y = (typeof y !== 'undefined') ? y : 0;
            }

            Point.prototype.clone = function () {
                return new Point(this.x, this.y);
            };
            Point.prototype.length = function (length) {
                if (typeof length == 'undefined')
                    return Math.sqrt(this.x * this.x + this.y * this.y);
                this.normalize();
                this.x *= length;
                this.y *= length;
                return this;
            };
            Point.prototype.normalize = function () {
                var length = this.length();
                this.x /= length;
                this.y /= length;
                return this;
            };
            return Point;
        })();

        /*
 * Particle class
 */
        var Particle = (function () {
            function Particle() {
                this.position = new Point();
                this.velocity = new Point();
                this.acceleration = new Point();
                this.age = 0;
            }

            Particle.prototype.initialize = function (x, y, dx, dy) {
                this.position.x = x;
                this.position.y = y;
                this.velocity.x = dx;
                this.velocity.y = dy;
                this.acceleration.x = dx * settings.particles.effect;
                this.acceleration.y = dy * settings.particles.effect;
                this.age = 0;
            };
            Particle.prototype.update = function (deltaTime) {
                this.position.x += this.velocity.x * deltaTime;
                this.position.y += this.velocity.y * deltaTime;
                this.velocity.x += this.acceleration.x * deltaTime;
                this.velocity.y += this.acceleration.y * deltaTime;
                this.age += deltaTime;
            };
            Particle.prototype.draw = function (context, image) {
                function ease(t) {
                    return (--t) * t * t + 1;
                }

                var size = image.width * ease(this.age / settings.particles.duration);
                context.globalAlpha = 1 - this.age / settings.particles.duration;
                context.drawImage(image, this.position.x - size / 2, this.position.y - size / 2, size, size);
            };
            return Particle;
        })();

        /*
 * ParticlePool class
 */
        var ParticlePool = (function () {
            var particles,
                firstActive = 0,
                firstFree = 0,
                duration = settings.particles.duration;

            function ParticlePool(length) {
                // create and populate particle pool
                particles = new Array(length);
                for (var i = 0; i < particles.length; i++)
                    particles[i] = new Particle();
            }

            ParticlePool.prototype.add = function (x, y, dx, dy) {
                particles[firstFree].initialize(x, y, dx, dy);

                // handle circular queue
                firstFree++;
                if (firstFree == particles.length) firstFree = 0;
                if (firstActive == firstFree) firstActive++;
                if (firstActive == particles.length) firstActive = 0;
            };
            ParticlePool.prototype.update = function (deltaTime) {
                var i;

                // update active particles
                if (firstActive < firstFree) {
                    for (i = firstActive; i < firstFree; i++)
                        particles[i].update(deltaTime);
                }
                if (firstFree < firstActive) {
                    for (i = firstActive; i < particles.length; i++)
                        particles[i].update(deltaTime);
                    for (i = 0; i < firstFree; i++)
                        particles[i].update(deltaTime);
                }

                // remove inactive particles
                while (particles[firstActive].age >= duration && firstActive != firstFree) {
                    firstActive++;
                    if (firstActive == particles.length) firstActive = 0;
                }


            };
            ParticlePool.prototype.draw = function (context, image) {
                // draw active particles
                if (firstActive < firstFree) {
                    for (i = firstActive; i < firstFree; i++)
                        particles[i].draw(context, image);
                }
                if (firstFree < firstActive) {
                    for (i = firstActive; i < particles.length; i++)
                        particles[i].draw(context, image);
                    for (i = 0; i < firstFree; i++)
                        particles[i].draw(context, image);
                }
            };
            return ParticlePool;
        })();

        /*
 * Putting it all together
 */
        var oBody = document.getElementsByTagName("body")[0];
        var canvas = document.createElement("canvas");
        canvas.id = 'pinkboard';
        // canvas.className='show_like';
        oBody.appendChild(canvas);
        (function (canvas) {
            var context = canvas.getContext('2d'),
                particles = new ParticlePool(settings.particles.length),
                particleRate = settings.particles.length / settings.particles.duration, // particles/sec
                time;

            // get point on heart with -PI <= t <= PI
            function pointOnHeart(t) {
                return new Point(
                    (160 * Math.pow(Math.sin(t), 3))*0.4,
                            (130 * Math.cos(t) - 50 * Math.cos(2 * t) - 20 * Math.cos(3 * t) - 10 * Math.cos(4 * t) + 25)*0.4);
            }

            // creating the particle image using a dummy canvas
            var image = (function () {
                var canvas = document.createElement('canvas'),
                    context = canvas.getContext('2d');
                $("canvas").css({
                    "width": "70%",
                    "position":"fixed",
                    "top":"25%",
                    "bottom":0,
                    "left":0,
                    "right":0,
                    "margin":"0 auto",
                    "height": "50%",
                    // "margin-top": "70%"
                });
                canvas.width = settings.particles.size;
                canvas.height = settings.particles.size;

                // helper function to create the path
                function to(t) {
                    var point = pointOnHeart(t);
                    point.x = settings.particles.size / 2 + point.x * settings.particles.size / 350;
                    point.y = settings.particles.size / 2 - point.y * settings.particles.size / 350;
                    return point;
                }

                // create the path
                context.beginPath();
                var t = -Math.PI;
                var point = to(t);
                context.moveTo(point.x, point.y);
                while (t < Math.PI) {
                    t += 0.01; // baby steps!
                    point = to(t);
                    context.lineTo(point.x, point.y);
                }
                context.closePath();
                // create the fill
                context.fillStyle = '#ea0e19';
                context.fill();
                // create the image
                var image = new Image();
                image.src = canvas.toDataURL();
                return image;
            })();

            // render that thing!
            function render() {
                // next animation frame
                requestAnimationFrame(render);

                // update time
                var newTime = new Date().getTime() / 1000,
                    deltaTime = newTime - (time || newTime);
                time = newTime;

                // clear canvas
                context.clearRect(0, 0, canvas.width, canvas.height);

                // create new particles
                var amount = particleRate * deltaTime;
                for (var i = 0; i < amount; i++) {
                    var pos = pointOnHeart(Math.PI - 2 * Math.PI * Math.random());
                    var dir = pos.clone().length(settings.particles.velocity);
                    particles.add(canvas.width / 2 + pos.x, canvas.height / 2 - pos.y, dir.x, -dir.y);
                }

                // update and draw particles
                particles.update(deltaTime);
                particles.draw(context, image);
            }

            // handle (re-)sizing of the canvas
            function onResize() {
                canvas.width = canvas.clientWidth;
                canvas.height = canvas.clientHeight;
            }

            window.onresize = onResize;

            // delay rendering bootstrap
            setTimeout(function () {
                onResize();
                render();
            }, 10);
        })(document.getElementById('pinkboard'));
    }
    function stop() {
        $("#pinkboard").addClass("hidden");
        setTimeout(function () {
            $("canvas").remove();
        },1000)
    }
</script>
</body>
</html>